Robert Orel Dean also known as Bob Dean, is a retired Command Sergeant Major in the US Army, who became notable in UFOlogy circles after he claimed to have viewed "Cosmic Top Secret" documents detailing alien activity on Earth.

In 1964, a USAF colonel, Col. Frank Collins, gave Dean, a Command Master Sergeant, access to a copy of a document called An Assessment. Dean stated that there were only 15 copies, one of which was kept in the safe. He said to read it every chance he had, being able to access the document because he had Cosmic Top Secret Clearance, As would be expected in the case of such a high-security classified document, Dean has been unable to provide a copy to prove his recount.

Dean states the document An Assessment: An Evaluation of a Possible Threat to Allied Forces in Europe (published in 1964) was a one and a half inch-thick secret NATO report on UFOs. The document was accompanied by eight and a half inches of Annexes and Appendices.

The report was ordered to be compiled by British Air Marshall Sir Thomas Geoffrey Pike, Deputy SACEUR (Deputy Supreme Allied Commander Europe) from August 1963 until his retirement in 1967. It was prompted by a Red Alert event that allegedly happened on 2nd February 1961 at 0200 hrs. A formation of approximately 50 flying disc-shaped objects flew at very high altitudes and speeds under intelligent control. They came from the east, flew over Germany, France, England and continued north until they disappeared over the Norwegian sea.

The titles of some of the annexes of the report, Dean states, were as follows: Radar and Electromagnetic Effects, Optical and Light Analysis, Photographic and Holographic Analysis, Historical Research and Historical Evidence, Metallurgical and Technical Analysis, Atmospheric Physics and Meteorology, Biological Analysis and Autopsies, Sociological Problems, Psychological Problems, Theological Implications, and Worldwide Effects.

"The Assessment" concluded, in 1964, that there were four different extraterrestrial civilizations visiting Earth, but by Dean’s retirement from the military in 1976, he claims, the report stated that there were at least twelve different extraterrestrial civilizations visiting Earth.